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Oracle9i Database Reference
Release 2 (9.2)

Part Number A96536-02
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Parameter type


Default value


Parameter class


Range of values

true | false

The value of SQL_TRACE disables or enables the SQL trace facility. Setting this parameter to true provides information on tuning that you can use to improve performance. You can change the value using the DBMS_SYSTEM package.


Using this initialization parameter to enable the SQL trace facility for the entire instance can have a severe performance impact. Enable the facility for specific sessions using the ALTER SESSION statement. If you must enable the facility on an entire production environment, you can minimize performance impact by:

  • Maintaining at least 25% idle CPU capacity
  • Maintaining adequate disk space for the USER_DUMP_DEST location
  • Striping disk space over sufficient disks


If you change the value of this parameter by using the ALTER SESSION SET SQL_TRACE statement, the resulting change will not be reflected in the V$PARAMETER dynamic performance view. Therefore, this parameter is not considered dynamic. For information on the ALTER SESSION statement, see Oracle9i SQL Reference.

See Also:

Oracle9i Database Performance Tuning Guide and Referencefor more information about performance diagnostic tools